arch/x86/include/asm/uaccess.h

   1 #ifndef _ASM_X86_UACCESS_H
   2 #define _ASM_X86_UACCESS_H
   3 /*
   4  * User space memory access functions
   5  */
   6 #include <linux/errno.h>
   7 #include <linux/compiler.h>
   8 #include <linux/thread_info.h>
   9 #include <linux/string.h>
  10 #include <linux/preempt.h>
  11 #include <asm/asm.h>
  12 #include <asm/page.h>
  13 #include <asm/smap.h>
  14
  15 #define VERIFY_READ 0
  16 #define VERIFY_WRITE 1
  17
  18 /*
  19  * The fs value determines whether argument validity checking should be
  20  * performed or not.  If get_fs() == USER_DS, checking is performed, with
  21  * get_fs() == KERNEL_DS, checking is bypassed.
  22  *
  23  * For historical reasons, these macros are grossly misnamed.
  24  */
  25
  26 #define MAKE_MM_SEG(s)  ((mm_segment_t) { (s) })
  27
  28 #define KERNEL_DS       MAKE_MM_SEG(-1UL)
  29 #define USER_DS         MAKE_MM_SEG(TASK_SIZE_MAX)
  30
  31 #define get_ds()        (KERNEL_DS)
  32 #define get_fs()        (current_thread_info()->addr_limit)
  33 #define set_fs(x)       (current_thread_info()->addr_limit = (x))
  34
  35 #define segment_eq(a, b)        ((a).seg == (b).seg)
  36
  37 #define user_addr_max() (current_thread_info()->addr_limit.seg)
  38 #define __addr_ok(addr)         \
  39         ((unsigned long __force)(addr) < user_addr_max())
  40
  41 /*
  42  * Test whether a block of memory is a valid user space address.
  43  * Returns 0 if the range is valid, nonzero otherwise.
  44  */
  45 static inline bool __chk_range_not_ok(unsigned long addr, unsigned long size, unsigned long limit)
  46 {
  47         /*
  48          * If we have used "sizeof()" for the size,
  49          * we know it won't overflow the limit (but
  50          * it might overflow the 'addr', so it's
  51          * important to subtract the size from the
  52          * limit, not add it to the address).
  53          */
  54         if (__builtin_constant_p(size))
  55                 return unlikely(addr > limit - size);
  56
  57         /* Arbitrary sizes? Be careful about overflow */
  58         addr += size;
  59         if (unlikely(addr < size))
  60                 return true;
  61         return unlikely(addr > limit);
  62 }
  63
  64 #define __range_not_ok(addr, size, limit)                               \
  65 ({                                                                      \
  66         __chk_user_ptr(addr);                                           \
  67         __chk_range_not_ok((unsigned long __force)(addr), size, limit); \
  68 })
  69
  70 #ifdef CONFIG_DEBUG_ATOMIC_SLEEP
  71 # define WARN_ON_IN_IRQ()       WARN_ON_ONCE(!in_task())
  72 #else
  73 # define WARN_ON_IN_IRQ()
  74 #endif
  75
  76 /**
  77  * access_ok: - Checks if a user space pointer is valid
  78  * @type: Type of access: %VERIFY_READ or %VERIFY_WRITE.  Note that
  79  *        %VERIFY_WRITE is a superset of %VERIFY_READ - if it is safe
  80  *        to write to a block, it is always safe to read from it.
  81  * @addr: User space pointer to start of block to check
  82  * @size: Size of block to check
  83  *
  84  * Context: User context only. This function may sleep if pagefaults are
  85  *          enabled.
  86  *
  87  * Checks if a pointer to a block of memory in user space is valid.
  88  *
  89  * Returns true (nonzero) if the memory block may be valid, false (zero)
  90  * if it is definitely invalid.
  91  *
  92  * Note that, depending on architecture, this function probably just
  93  * checks that the pointer is in the user space range - after calling
  94  * this function, memory access functions may still return -EFAULT.
  95  */
  96 #define access_ok(type, addr, size)                                     \
  97 ({                                                                      \
  98         WARN_ON_IN_IRQ();                                               \
  99         likely(!__range_not_ok(addr, size, user_addr_max()));           \
 100 })
 101
 102 /*
 103  * The exception table consists of pairs of addresses relative to the
 104  * exception table enty itself: the first is the address of an
 105  * instruction that is allowed to fault, and the second is the address
 106  * at which the program should continue.  No registers are modified,
 107  * so it is entirely up to the continuation code to figure out what to
 108  * do.
 109  *
 110  * All the routines below use bits of fixup code that are out of line
 111  * with the main instruction path.  This means when everything is well,
 112  * we don't even have to jump over them.  Further, they do not intrude
 113  * on our cache or tlb entries.
 114  */
 115
 116 struct exception_table_entry {
 117         int insn, fixup;
 118 };
 119 /* This is not the generic standard exception_table_entry format */
 120 #define ARCH_HAS_SORT_EXTABLE
 121 #define ARCH_HAS_SEARCH_EXTABLE
 122
 123 extern int fixup_exception(struct pt_regs *regs);
 124 extern int early_fixup_exception(unsigned long *ip);
 125
 126 /*
 127  * These are the main single-value transfer routines.  They automatically
 128  * use the right size if we just have the right pointer type.
 129  *
 130  * This gets kind of ugly. We want to return _two_ values in "get_user()"
 131  * and yet we don't want to do any pointers, because that is too much
 132  * of a performance impact. Thus we have a few rather ugly macros here,
 133  * and hide all the ugliness from the user.
 134  *
 135  * The "__xxx" versions of the user access functions are versions that
 136  * do not verify the address space, that must have been done previously
 137  * with a separate "access_ok()" call (this is used when we do multiple
 138  * accesses to the same area of user memory).
 139  */
 140
 141 extern int __get_user_1(void);
 142 extern int __get_user_2(void);
 143 extern int __get_user_4(void);
 144 extern int __get_user_8(void);
 145 extern int __get_user_bad(void);
 146
 147 #define __uaccess_begin() stac()
 148 #define __uaccess_end()   clac()
 149 #define __uaccess_begin_nospec()        \
 150 ({                                      \
 151         stac();                         \
 152         barrier_nospec();               \
 153 })
 154
 155 /*
 156  * This is a type: either unsigned long, if the argument fits into
 157  * that type, or otherwise unsigned long long.
 158  */
 159 #define __inttype(x) \
 160 __typeof__(__builtin_choose_expr(sizeof(x) > sizeof(0UL), 0ULL, 0UL))
 161
 162 /**
 163  * get_user: - Get a simple variable from user space.
 164  * @x:   Variable to store result.
 165  * @ptr: Source address, in user space.
 166  *
 167  * Context: User context only. This function may sleep if pagefaults are
 168  *          enabled.
 169  *
 170  * This macro copies a single simple variable from user space to kernel
 171  * space.  It supports simple types like char and int, but not larger
 172  * data types like structures or arrays.
 173  *
 174  * @ptr must have pointer-to-simple-variable type, and the result of
 175  * dereferencing @ptr must be assignable to @x without a cast.
 176  *
 177  * Returns zero on success, or -EFAULT on error.
 178  * On error, the variable @x is set to zero.
 179  */
 180 /*
 181  * Careful: we have to cast the result to the type of the pointer
 182  * for sign reasons.
 183  *
 184  * The use of _ASM_DX as the register specifier is a bit of a
 185  * simplification, as gcc only cares about it as the starting point
 186  * and not size: for a 64-bit value it will use %ecx:%edx on 32 bits
 187  * (%ecx being the next register in gcc's x86 register sequence), and
 188  * %rdx on 64 bits.
 189  *
 190  * Clang/LLVM cares about the size of the register, but still wants
 191  * the base register for something that ends up being a pair.
 192  */
 193 #define get_user(x, ptr)                                                \
 194 ({                                                                      \
 195         int __ret_gu;                                                   \
 196         register __inttype(*(ptr)) __val_gu asm("%"_ASM_DX);            \
 197         __chk_user_ptr(ptr);                                            \
 198         might_fault();                                                  \
 199         asm volatile("call __get_user_%P3"                              \
 200                      : "=a" (__ret_gu), "=r" (__val_gu)                 \
 201                      : "0" (ptr), "i" (sizeof(*(ptr))));                \
 202         (x) = (__force __typeof__(*(ptr))) __val_gu;                    \
 203         __builtin_expect(__ret_gu, 0);                                  \
 204 })
 205
 206 #define __put_user_x(size, x, ptr, __ret_pu)                    \
 207         asm volatile("call __put_user_" #size : "=a" (__ret_pu) \
 208                      : "0" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 209
 210
 211
 212 #ifdef CONFIG_X86_32
 213 #define __put_user_asm_u64(x, addr, err, errret)                        \
 214         asm volatile("\n"                                               \
 215                      "1:        movl %%eax,0(%2)\n"                     \
 216                      "2:        movl %%edx,4(%2)\n"                     \
 217                      "3:"                                               \
 218                      ".section .fixup,\"ax\"\n"                         \
 219                      "4:        movl %3,%0\n"                           \
 220                      "  jmp 3b\n"                                       \
 221                      ".previous\n"                                      \
 222                      _ASM_EXTABLE(1b, 4b)                               \
 223                      _ASM_EXTABLE(2b, 4b)                               \
 224                      : "=r" (err)                                       \
 225                      : "A" (x), "r" (addr), "i" (errret), "0" (err))
 226
 227 #define __put_user_asm_ex_u64(x, addr)                                  \
 228         asm volatile("\n"                                               \
 229                      "1:        movl %%eax,0(%1)\n"                     \
 230                      "2:        movl %%edx,4(%1)\n"                     \
 231                      "3:"                                               \
 232                      _ASM_EXTABLE_EX(1b, 2b)                            \
 233                      _ASM_EXTABLE_EX(2b, 3b)                            \
 234                      : : "A" (x), "r" (addr))
 235
 236 #define __put_user_x8(x, ptr, __ret_pu)                         \
 237         asm volatile("call __put_user_8" : "=a" (__ret_pu)      \
 238                      : "A" ((typeof(*(ptr)))(x)), "c" (ptr) : "ebx")
 239 #else
 240 #define __put_user_asm_u64(x, ptr, retval, errret) \
 241         __put_user_asm(x, ptr, retval, "q", "", "er", errret)
 242 #define __put_user_asm_ex_u64(x, addr)  \
 243         __put_user_asm_ex(x, addr, "q", "", "er")
 244 #define __put_user_x8(x, ptr, __ret_pu) __put_user_x(8, x, ptr, __ret_pu)
 245 #endif
 246
 247 extern void __put_user_bad(void);
 248
 249 /*
 250  * Strange magic calling convention: pointer in %ecx,
 251  * value in %eax(:%edx), return value in %eax. clobbers %rbx
 252  */
 253 extern void __put_user_1(void);
 254 extern void __put_user_2(void);
 255 extern void __put_user_4(void);
 256 extern void __put_user_8(void);
 257
 258 /**
 259  * put_user: - Write a simple value into user space.
 260  * @x:   Value to copy to user space.
 261  * @ptr: Destination address, in user space.
 262  *
 263  * Context: User context only. This function may sleep if pagefaults are
 264  *          enabled.
 265  *
 266  * This macro copies a single simple value from kernel space to user
 267  * space.  It supports simple types like char and int, but not larger
 268  * data types like structures or arrays.
 269  *
 270  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 271  * to the result of dereferencing @ptr.
 272  *
 273  * Returns zero on success, or -EFAULT on error.
 274  */
 275 #define put_user(x, ptr)                                        \
 276 ({                                                              \
 277         int __ret_pu;                                           \
 278         __typeof__(*(ptr)) __pu_val;                            \
 279         __chk_user_ptr(ptr);                                    \
 280         might_fault();                                          \
 281         __pu_val = x;                                           \
 282         switch (sizeof(*(ptr))) {                               \
 283         case 1:                                                 \
 284                 __put_user_x(1, __pu_val, ptr, __ret_pu);       \
 285                 break;                                          \
 286         case 2:                                                 \
 287                 __put_user_x(2, __pu_val, ptr, __ret_pu);       \
 288                 break;                                          \
 289         case 4:                                                 \
 290                 __put_user_x(4, __pu_val, ptr, __ret_pu);       \
 291                 break;                                          \
 292         case 8:                                                 \
 293                 __put_user_x8(__pu_val, ptr, __ret_pu);         \
 294                 break;                                          \
 295         default:                                                \
 296                 __put_user_x(X, __pu_val, ptr, __ret_pu);       \
 297                 break;                                          \
 298         }                                                       \
 299         __builtin_expect(__ret_pu, 0);                          \
 300 })
 301
 302 #define __put_user_size(x, ptr, size, retval, errret)                   \
 303 do {                                                                    \
 304         retval = 0;                                                     \
 305         __chk_user_ptr(ptr);                                            \
 306         switch (size) {                                                 \
 307         case 1:                                                         \
 308                 __put_user_asm(x, ptr, retval, "b", "b", "iq", errret); \
 309                 break;                                                  \
 310         case 2:                                                         \
 311                 __put_user_asm(x, ptr, retval, "w", "w", "ir", errret); \
 312                 break;                                                  \
 313         case 4:                                                         \
 314                 __put_user_asm(x, ptr, retval, "l", "k", "ir", errret); \
 315                 break;                                                  \
 316         case 8:                                                         \
 317                 __put_user_asm_u64(x, ptr, retval, errret);             \
 318                 break;                                                  \
 319         default:                                                        \
 320                 __put_user_bad();                                       \
 321         }                                                               \
 322 } while (0)
 323
 324 /*
 325  * This doesn't do __uaccess_begin/end - the exception handling
 326  * around it must do that.
 327  */
 328 #define __put_user_size_ex(x, ptr, size)                                \
 329 do {                                                                    \
 330         __chk_user_ptr(ptr);                                            \
 331         switch (size) {                                                 \
 332         case 1:                                                         \
 333                 __put_user_asm_ex(x, ptr, "b", "b", "iq");              \
 334                 break;                                                  \
 335         case 2:                                                         \
 336                 __put_user_asm_ex(x, ptr, "w", "w", "ir");              \
 337                 break;                                                  \
 338         case 4:                                                         \
 339                 __put_user_asm_ex(x, ptr, "l", "k", "ir");              \
 340                 break;                                                  \
 341         case 8:                                                         \
 342                 __put_user_asm_ex_u64((__typeof__(*ptr))(x), ptr);      \
 343                 break;                                                  \
 344         default:                                                        \
 345                 __put_user_bad();                                       \
 346         }                                                               \
 347 } while (0)
 348
 349 #ifdef CONFIG_X86_32
 350 #define __get_user_asm_u64(x, ptr, retval, errret)      (x) = __get_user_bad()
 351 #define __get_user_asm_ex_u64(x, ptr)                   (x) = __get_user_bad()
 352 #else
 353 #define __get_user_asm_u64(x, ptr, retval, errret) \
 354          __get_user_asm(x, ptr, retval, "q", "", "=r", errret)
 355 #define __get_user_asm_ex_u64(x, ptr) \
 356          __get_user_asm_ex(x, ptr, "q", "", "=&r")
 357 #endif
 358
 359 #define __get_user_size(x, ptr, size, retval, errret)                   \
 360 do {                                                                    \
 361         retval = 0;                                                     \
 362         __chk_user_ptr(ptr);                                            \
 363         switch (size) {                                                 \
 364         case 1:                                                         \
 365                 __get_user_asm(x, ptr, retval, "b", "b", "=q", errret); \
 366                 break;                                                  \
 367         case 2:                                                         \
 368                 __get_user_asm(x, ptr, retval, "w", "w", "=r", errret); \
 369                 break;                                                  \
 370         case 4:                                                         \
 371                 __get_user_asm(x, ptr, retval, "l", "k", "=r", errret); \
 372                 break;                                                  \
 373         case 8:                                                         \
 374                 __get_user_asm_u64(x, ptr, retval, errret);             \
 375                 break;                                                  \
 376         default:                                                        \
 377                 (x) = __get_user_bad();                                 \
 378         }                                                               \
 379 } while (0)
 380
 381 #define __get_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
 382         asm volatile("\n"                                               \
 383                      "1:        mov"itype" %2,%"rtype"1\n"              \
 384                      "2:\n"                                             \
 385                      ".section .fixup,\"ax\"\n"                         \
 386                      "3:        mov %3,%0\n"                            \
 387                      "  xor"itype" %"rtype"1,%"rtype"1\n"               \
 388                      "  jmp 2b\n"                                       \
 389                      ".previous\n"                                      \
 390                      _ASM_EXTABLE(1b, 3b)                               \
 391                      : "=r" (err), ltype(x)                             \
 392                      : "m" (__m(addr)), "i" (errret), "0" (err))
 393
 394 /*
 395  * This doesn't do __uaccess_begin/end - the exception handling
 396  * around it must do that.
 397  */
 398 #define __get_user_size_ex(x, ptr, size)                                \
 399 do {                                                                    \
 400         __chk_user_ptr(ptr);                                            \
 401         switch (size) {                                                 \
 402         case 1:                                                         \
 403                 __get_user_asm_ex(x, ptr, "b", "b", "=&q");             \
 404                 break;                                                  \
 405         case 2:                                                         \
 406                 __get_user_asm_ex(x, ptr, "w", "w", "=&r");             \
 407                 break;                                                  \
 408         case 4:                                                         \
 409                 __get_user_asm_ex(x, ptr, "l", "k", "=&r");             \
 410                 break;                                                  \
 411         case 8:                                                         \
 412                 __get_user_asm_ex_u64(x, ptr);                          \
 413                 break;                                                  \
 414         default:                                                        \
 415                 (x) = __get_user_bad();                                 \
 416         }                                                               \
 417 } while (0)
 418
 419 #define __get_user_asm_ex(x, addr, itype, rtype, ltype)                 \
 420         asm volatile("1:        mov"itype" %1,%"rtype"0\n"              \
 421                      "2:\n"                                             \
 422                      _ASM_EXTABLE_EX(1b, 2b)                            \
 423                      : ltype(x) : "m" (__m(addr)), "0" (0))
 424
 425 #define __put_user_nocheck(x, ptr, size)                        \
 426 ({                                                              \
 427         int __pu_err;                                           \
 428         __typeof__(*(ptr)) __pu_val;                            \
 429         __pu_val = x;                                           \
 430         __uaccess_begin();                                      \
 431         __put_user_size(__pu_val, (ptr), (size), __pu_err, -EFAULT);\
 432         __uaccess_end();                                        \
 433         __builtin_expect(__pu_err, 0);                          \
 434 })
 435
 436 #define __get_user_nocheck(x, ptr, size)                                \
 437 ({                                                                      \
 438         int __gu_err;                                                   \
 439         unsigned long __gu_val;                                         \
 440         __uaccess_begin_nospec();                                       \
 441         __get_user_size(__gu_val, (ptr), (size), __gu_err, -EFAULT);    \
 442         __uaccess_end();                                                \
 443         (x) = (__force __typeof__(*(ptr)))__gu_val;                     \
 444         __builtin_expect(__gu_err, 0);                                  \
 445 })
 446
 447 /* FIXME: this hack is definitely wrong -AK */
 448 struct __large_struct { unsigned long buf[100]; };
 449 #define __m(x) (*(struct __large_struct __user *)(x))
 450
 451 /*
 452  * Tell gcc we read from memory instead of writing: this is because
 453  * we do not write to any memory gcc knows about, so there are no
 454  * aliasing issues.
 455  */
 456 #define __put_user_asm(x, addr, err, itype, rtype, ltype, errret)       \
 457         asm volatile("\n"                                               \
 458                      "1:        mov"itype" %"rtype"1,%2\n"              \
 459                      "2:\n"                                             \
 460                      ".section .fixup,\"ax\"\n"                         \
 461                      "3:        mov %3,%0\n"                            \
 462                      "  jmp 2b\n"                                       \
 463                      ".previous\n"                                      \
 464                      _ASM_EXTABLE(1b, 3b)                               \
 465                      : "=r"(err)                                        \
 466                      : ltype(x), "m" (__m(addr)), "i" (errret), "0" (err))
 467
 468 #define __put_user_asm_ex(x, addr, itype, rtype, ltype)                 \
 469         asm volatile("1:        mov"itype" %"rtype"0,%1\n"              \
 470                      "2:\n"                                             \
 471                      _ASM_EXTABLE_EX(1b, 2b)                            \
 472                      : : ltype(x), "m" (__m(addr)))
 473
 474 /*
 475  * uaccess_try and catch
 476  */
 477 #define uaccess_try     do {                                            \
 478         current_thread_info()->uaccess_err = 0;                         \
 479         __uaccess_begin();                                              \
 480         barrier();
 481
 482 #define uaccess_try_nospec do {                                         \
 483         current_thread_info()->uaccess_err = 0;                         \
 484         __uaccess_begin_nospec();                                       \
 485
 486 #define uaccess_catch(err)                                              \
 487         __uaccess_end();                                                \
 488         (err) |= (current_thread_info()->uaccess_err ? -EFAULT : 0);    \
 489 } while (0)
 490
 491 /**
 492  * __get_user: - Get a simple variable from user space, with less checking.
 493  * @x:   Variable to store result.
 494  * @ptr: Source address, in user space.
 495  *
 496  * Context: User context only. This function may sleep if pagefaults are
 497  *          enabled.
 498  *
 499  * This macro copies a single simple variable from user space to kernel
 500  * space.  It supports simple types like char and int, but not larger
 501  * data types like structures or arrays.
 502  *
 503  * @ptr must have pointer-to-simple-variable type, and the result of
 504  * dereferencing @ptr must be assignable to @x without a cast.
 505  *
 506  * Caller must check the pointer with access_ok() before calling this
 507  * function.
 508  *
 509  * Returns zero on success, or -EFAULT on error.
 510  * On error, the variable @x is set to zero.
 511  */
 512
 513 #define __get_user(x, ptr)                                              \
 514         __get_user_nocheck((x), (ptr), sizeof(*(ptr)))
 515
 516 /**
 517  * __put_user: - Write a simple value into user space, with less checking.
 518  * @x:   Value to copy to user space.
 519  * @ptr: Destination address, in user space.
 520  *
 521  * Context: User context only. This function may sleep if pagefaults are
 522  *          enabled.
 523  *
 524  * This macro copies a single simple value from kernel space to user
 525  * space.  It supports simple types like char and int, but not larger
 526  * data types like structures or arrays.
 527  *
 528  * @ptr must have pointer-to-simple-variable type, and @x must be assignable
 529  * to the result of dereferencing @ptr.
 530  *
 531  * Caller must check the pointer with access_ok() before calling this
 532  * function.
 533  *
 534  * Returns zero on success, or -EFAULT on error.
 535  */
 536
 537 #define __put_user(x, ptr)                                              \
 538         __put_user_nocheck((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 539
 540 #define __get_user_unaligned __get_user
 541 #define __put_user_unaligned __put_user
 542
 543 /*
 544  * {get|put}_user_try and catch
 545  *
 546  * get_user_try {
 547  *      get_user_ex(...);
 548  * } get_user_catch(err)
 549  */
 550 #define get_user_try            uaccess_try_nospec
 551 #define get_user_catch(err)     uaccess_catch(err)
 552
 553 #define get_user_ex(x, ptr)     do {                                    \
 554         unsigned long __gue_val;                                        \
 555         __get_user_size_ex((__gue_val), (ptr), (sizeof(*(ptr))));       \
 556         (x) = (__force __typeof__(*(ptr)))__gue_val;                    \
 557 } while (0)
 558
 559 #define put_user_try            uaccess_try
 560 #define put_user_catch(err)     uaccess_catch(err)
 561
 562 #define put_user_ex(x, ptr)                                             \
 563         __put_user_size_ex((__typeof__(*(ptr)))(x), (ptr), sizeof(*(ptr)))
 564
 565 extern unsigned long
 566 copy_from_user_nmi(void *to, const void __user *from, unsigned long n);
 567 extern __must_check long
 568 strncpy_from_user(char *dst, const char __user *src, long count);
 569
 570 extern __must_check long strlen_user(const char __user *str);
 571 extern __must_check long strnlen_user(const char __user *str, long n);
 572
 573 unsigned long __must_check clear_user(void __user *mem, unsigned long len);
 574 unsigned long __must_check __clear_user(void __user *mem, unsigned long len);
 575
 576 extern void __cmpxchg_wrong_size(void)
 577         __compiletime_error("Bad argument size for cmpxchg");
 578
 579 #define __user_atomic_cmpxchg_inatomic(uval, ptr, old, new, size)       \
 580 ({                                                                      \
 581         int __ret = 0;                                                  \
 582         __typeof__(ptr) __uval = (uval);                                \
 583         __typeof__(*(ptr)) __old = (old);                               \
 584         __typeof__(*(ptr)) __new = (new);                               \
 585         __uaccess_begin_nospec();                                       \
 586         switch (size) {                                                 \
 587         case 1:                                                         \
 588         {                                                               \
 589                 asm volatile("\n"                                       \
 590                         "1:\t" LOCK_PREFIX "cmpxchgb %4, %2\n"          \
 591                         "2:\n"                                          \
 592                         "\t.section .fixup, \"ax\"\n"                   \
 593                         "3:\tmov     %3, %0\n"                          \
 594                         "\tjmp     2b\n"                                \
 595                         "\t.previous\n"                                 \
 596                         _ASM_EXTABLE(1b, 3b)                            \
 597                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 598                         : "i" (-EFAULT), "q" (__new), "1" (__old)       \
 599                         : "memory"                                      \
 600                 );                                                      \
 601                 break;                                                  \
 602         }                                                               \
 603         case 2:                                                         \
 604         {                                                               \
 605                 asm volatile("\n"                                       \
 606                         "1:\t" LOCK_PREFIX "cmpxchgw %4, %2\n"          \
 607                         "2:\n"                                          \
 608                         "\t.section .fixup, \"ax\"\n"                   \
 609                         "3:\tmov     %3, %0\n"                          \
 610                         "\tjmp     2b\n"                                \
 611                         "\t.previous\n"                                 \
 612                         _ASM_EXTABLE(1b, 3b)                            \
 613                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 614                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 615                         : "memory"                                      \
 616                 );                                                      \
 617                 break;                                                  \
 618         }                                                               \
 619         case 4:                                                         \
 620         {                                                               \
 621                 asm volatile("\n"                                       \
 622                         "1:\t" LOCK_PREFIX "cmpxchgl %4, %2\n"          \
 623                         "2:\n"                                          \
 624                         "\t.section .fixup, \"ax\"\n"                   \
 625                         "3:\tmov     %3, %0\n"                          \
 626                         "\tjmp     2b\n"                                \
 627                         "\t.previous\n"                                 \
 628                         _ASM_EXTABLE(1b, 3b)                            \
 629                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 630                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 631                         : "memory"                                      \
 632                 );                                                      \
 633                 break;                                                  \
 634         }                                                               \
 635         case 8:                                                         \
 636         {                                                               \
 637                 if (!IS_ENABLED(CONFIG_X86_64))                         \
 638                         __cmpxchg_wrong_size();                         \
 639                                                                         \
 640                 asm volatile("\n"                                       \
 641                         "1:\t" LOCK_PREFIX "cmpxchgq %4, %2\n"          \
 642                         "2:\n"                                          \
 643                         "\t.section .fixup, \"ax\"\n"                   \
 644                         "3:\tmov     %3, %0\n"                          \
 645                         "\tjmp     2b\n"                                \
 646                         "\t.previous\n"                                 \
 647                         _ASM_EXTABLE(1b, 3b)                            \
 648                         : "+r" (__ret), "=a" (__old), "+m" (*(ptr))     \
 649                         : "i" (-EFAULT), "r" (__new), "1" (__old)       \
 650                         : "memory"                                      \
 651                 );                                                      \
 652                 break;                                                  \
 653         }                                                               \
 654         default:                                                        \
 655                 __cmpxchg_wrong_size();                                 \
 656         }                                                               \
 657         __uaccess_end();                                                \
 658         *__uval = __old;                                                \
 659         __ret;                                                          \
 660 })
 661
 662 #define user_atomic_cmpxchg_inatomic(uval, ptr, old, new)               \
 663 ({                                                                      \
 664         access_ok(VERIFY_WRITE, (ptr), sizeof(*(ptr))) ?                \
 665                 __user_atomic_cmpxchg_inatomic((uval), (ptr),           \
 666                                 (old), (new), sizeof(*(ptr))) :         \
 667                 -EFAULT;                                                \
 668 })
 669
 670 /*
 671  * movsl can be slow when source and dest are not both 8-byte aligned
 672  */
 673 #ifdef CONFIG_X86_INTEL_USERCOPY
 674 extern struct movsl_mask {
 675         int mask;
 676 } ____cacheline_aligned_in_smp movsl_mask;
 677 #endif
 678
 679 #define ARCH_HAS_NOCACHE_UACCESS 1
 680
 681 #ifdef CONFIG_X86_32
 682 # include <asm/uaccess_32.h>
 683 #else
 684 # include <asm/uaccess_64.h>
 685 #endif
 686
 687 unsigned long __must_check _copy_from_user(void *to, const void __user *from,
 688                                            unsigned n);
 689 unsigned long __must_check _copy_to_user(void __user *to, const void *from,
 690                                          unsigned n);
 691
 692 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 693 # define copy_user_diag __compiletime_error
 694 #else
 695 # define copy_user_diag __compiletime_warning
 696 #endif
 697
 698 extern void copy_user_diag("copy_from_user() buffer size is too small")
 699 copy_from_user_overflow(void);
 700 extern void copy_user_diag("copy_to_user() buffer size is too small")
 701 copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
 702
 703 #undef copy_user_diag
 704
 705 #ifdef CONFIG_DEBUG_STRICT_USER_COPY_CHECKS
 706
 707 extern void
 708 __compiletime_warning("copy_from_user() buffer size is not provably correct")
 709 __copy_from_user_overflow(void) __asm__("copy_from_user_overflow");
 710 #define __copy_from_user_overflow(size, count) __copy_from_user_overflow()
 711
 712 extern void
 713 __compiletime_warning("copy_to_user() buffer size is not provably correct")
 714 __copy_to_user_overflow(void) __asm__("copy_from_user_overflow");
 715 #define __copy_to_user_overflow(size, count) __copy_to_user_overflow()
 716
 717 #else
 718
 719 static inline void
 720 __copy_from_user_overflow(int size, unsigned long count)
 721 {
 722         WARN(1, "Buffer overflow detected (%d < %lu)!\n", size, count);
 723 }
 724
 725 #define __copy_to_user_overflow __copy_from_user_overflow
 726
 727 #endif
 728
 729 static inline unsigned long __must_check
 730 copy_from_user(void *to, const void __user *from, unsigned long n)
 731 {
 732         int sz = __compiletime_object_size(to);
 733
 734         might_fault();
 735
 736         /*
 737          * While we would like to have the compiler do the checking for us
 738          * even in the non-constant size case, any false positives there are
 739          * a problem (especially when DEBUG_STRICT_USER_COPY_CHECKS, but even
 740          * without - the [hopefully] dangerous looking nature of the warning
 741          * would make people go look at the respecitive call sites over and
 742          * over again just to find that there's no problem).
 743          *
 744          * And there are cases where it's just not realistic for the compiler
 745          * to prove the count to be in range. For example when multiple call
 746          * sites of a helper function - perhaps in different source files -
 747          * all doing proper range checking, yet the helper function not doing
 748          * so again.
 749          *
 750          * Therefore limit the compile time checking to the constant size
 751          * case, and do only runtime checking for non-constant sizes.
 752          */
 753
 754         if (likely(sz < 0 || sz >= n))
 755                 n = _copy_from_user(to, from, n);
 756         else if(__builtin_constant_p(n))
 757                 copy_from_user_overflow();
 758         else
 759                 __copy_from_user_overflow(sz, n);
 760
 761         return n;
 762 }
 763
 764 static inline unsigned long __must_check
 765 copy_to_user(void __user *to, const void *from, unsigned long n)
 766 {
 767         int sz = __compiletime_object_size(from);
 768
 769         might_fault();
 770
 771         /* See the comment in copy_from_user() above. */
 772         if (likely(sz < 0 || sz >= n))
 773                 n = _copy_to_user(to, from, n);
 774         else if(__builtin_constant_p(n))
 775                 copy_to_user_overflow();
 776         else
 777                 __copy_to_user_overflow(sz, n);
 778
 779         return n;
 780 }
 781
 782 #undef __copy_from_user_overflow
 783 #undef __copy_to_user_overflow
 784
 785 #endif /* _ASM_X86_UACCESS_H */
 786